Fix HasMenuCurrent and IsDescendant/IsAncestor when comparing to itself

There may be sites in the wild that depends on the faulty behaviour of IsDescendant/IsAncestor when comparing to itself, but

* The documentation and common sense says that a thing cannot be descendant or ancestor to itself.
* The bug introduced in `HasMenuCurrent` comes directly from that confusion.

Fixes #9846

1 files changed, 6 insertions, 8 deletions

diff --git a/hugolib/page__tree.go b/hugolib/page__tree.go
index d2b1f684a..828500e62 100644
--- a/hugolib/page__tree.go
+++ b/hugolib/page__tree.go
@@ -36,6 +36,9 @@ func (pt pageTree) IsAncestor(other any) (bool, error) {
 	}
 
 	ref1, ref2 := pt.p.getTreeRef(), tp.getTreeRef()
+	if ref1 != nil && ref2 != nil && ref1.key == ref2.key {
+		return false, nil
+	}
 
 	if ref1 != nil && ref1.key == "/" {
 		return true, nil
@@ -50,10 +53,6 @@ func (pt pageTree) IsAncestor(other any) (bool, error) {
 		return ref1.n.p.IsHome(), nil
 	}
 
-	if ref1.key == ref2.key {
-		return true, nil
-	}
-
 	if strings.HasPrefix(ref2.key, ref1.key) {
 		return true, nil
 	}
@@ -82,6 +81,9 @@ func (pt pageTree) IsDescendant(other any) (bool, error) {
 	}
 
 	ref1, ref2 := pt.p.getTreeRef(), tp.getTreeRef()
+	if ref1 != nil && ref2 != nil && ref1.key == ref2.key {
+		return false, nil
+	}
 
 	if ref2 != nil && ref2.key == "/" {
 		return true, nil
@@ -96,10 +98,6 @@ func (pt pageTree) IsDescendant(other any) (bool, error) {
 		return ref2.n.p.IsHome(), nil
 	}
 
-	if ref1.key == ref2.key {
-		return true, nil
-	}
-
 	if strings.HasPrefix(ref1.key, ref2.key) {
 		return true, nil
 	}